I think in two ways worst than an alien disease, that can be a huge problem if in wrong hands.
The FIRST CASE SCENARIO is about miscalculation: capturing near Earth Asteroid is a complex challenge. One thing wrong and you could bombard Earth and cause serious problems (and billions of victims).
The SECOND CASE SCENARIO is hypothetical: what about finding a lot of tons of one or more of the 8 most expensive elements in the periodic table: Au, Ag, Pt, Pd, Ir, Rh, Os and Ru (or the worst case scenario: only

Actually, they do. I recall seeing an interview with the people at NASA behind this project on CBS. They said that the goal would be to mine captured asteroids for two things: valuable metals (they specified platinum, but there are probably plenty of others) and ice. The ice is particularly important because it can be used to obtain hydrogen and oxygen, which most rockets use for fuel. The NASA guy CBS interviewed had a vision of miniature space stations orbiting asteroids that would serve as the space equivalent of gas stations for long-range spaceflights, but who knows how viable that is.

Setting up gas stations in the asteroid belt could work quite well, I would think.

I begin to see the point of NASA's interest in mining the asteroids. It might be possible that water could be extracted from an asteroid by a solar powered satellite, then shipped by cheap, slow, unmanned rockets to rendezvous points for manned missions. Water has some excellent qualities for use as reactive mass in rocket motors, especially those with nuclear rather than chemical heaters, and a ship that only needed to carry

First there is a need to identify what exactly these manned missions are going to accomplish. Saving humanity ? No, the earth is a much better bet. Exploration ? No, much better and cheaper with robots. What else ? And without extended manned missions, what's the point of mining the asteroids ?

You can't capture a 10-20 mile per second asteroid, unless you speed up to that speed, and go along with it, or you ping pong it with weapons/bullets/objects to another desired speed, but if you're not going the same speed, it flies by you off and away like an ambulance with a siren. The best way to capture asteroids is to seek ones with near-miss orbits with the Moon or Earth, like (i'm talking shooting stars in August, when Earth flies through that domain) and modify their path to impact directly into the

You can use 100% of an asteroid's mass for useful items. After you extract water, carbon, and metals, the leftover slag can still serve as radiation shielding. Shielding is needed anywhere above low Earth orbit that you plan to spend much time at.

This yet another lame attempt by the all-powerful manned-spaceflight lobby at NASA to supply pork to politically powerful districts such as Houston. The SLS has been called the Rocket to Nowhere and this is an attempt to justify it.
All this fooling around with an asteroid could be done for a fraction of the cost with robotic probes.
And there is little gain scientifically from this mission.
The NASA administrator Bolden, a big-time manned spaceflight guy, has said that there will be no more flagship planetary missions (such as major missions to Mars or Europa), but he is more than willing to fund this asteroid capture stunt. So he wants to sacrifice science for pork.
Next year NASA/JPL will have robotic probes reach Pluto/Charon and Ceres, but all the administrator can talk about is this stupid asteroid stunt.

All this fooling around with an asteroid could be done for a fraction of the cost with robotic probes.

Yes... and no.

A significant portion of the proposed project is technology development. This mission puts together and demonstrates a large, high power solar-electric propulsion system, which would be a valuable tool for many missions, including human missions to Mars, or to anywhere. Then it gives us a target for a short-duration human exploration mission, testing the spacecraft concepts that could be accomplished,with a much less complicated mission than a Mars mission, or even a Mars fly-by.

Manned space flight, including human exploration of Mars is a pointless waste of time and money. Mars is an extremely hostile environment, and humans have no business being there, except as a brief stunt.

I know right, there was no point in going to the moon either, or to the poles, or anywhere else that doesn't have direct benefits in and of itself. Who cares about all this great science and technology that came about because of the process.

Sure, it's nice to get the spin-off technology, but you can also get that while aiming for a goal that actually has a purpose. A human settlement on Mars is about as useful as a self-supporting resort in the middle of the Gobi desert, and I don't see anybody rushing to build that.

The Gobi desert or the top of Mt. Everest or the Dry Valleys of Antarctica are, to paraphrase Sam Kinison, like Club Med compared to Mars. A human settlement on Mars would never be self-sustaining (no resources, limited energy, and no minerals) and could never flourish (the children would be weird stick figures that could never come back to Earth). On top of everything else would be the extremely unhealthy environment of dust, radiation, and low G.

Less energy and resources than the Gobi desert. And while Mars has plenty of minerals (like the Gobi desert), it will take a huge infrastructure to collect the ores and process them into useful forms. We have enough trouble landing a 1 ton rover on Mars. Imagine what it would take to send a steel smelter.

There are few if any minerals except iron and various evaporates such as sulfur, salt, calcium, magnesium, etc. Try finding copper on mars; good luck with that or most of the other industrial metals. Maybe nickle from meteorites and possibly platinum from the same source.
The problem is that there was never any plate tectonics on Mars to concentrate minerals.

The technology development would be really valuable if you believe in a future for human presence in space (which I do, but which I admit is an almost religious belief). The actual asteroid capture on the other hand seems like a difficult but not particularly interesting stunt. 10M isn't really an asteroid, its a rock. Rocks that size hit the earth regularly.

Personally I'd rather see the solar-electric propulsion developed for large probes, especially an Europa lander / rover, and maybe a Titan lander or

How is there little to gain scientifically from this mission? If we're able to capture an asteroid in space, how can we not learn anything from that? It's a fucking 6 meter boulder screaming by the earth at thousands of miles an hour! I would think the challenge of matching orbits, latching on to an object with almost no gravitational pull and sending it into an orbit around the moon would give us plenty of science to pour over for years to come.

You could send an expedition to Antarctica for a tiny fraction of the cost to collect pieces of asteroids called meteorites! Ooops, we already do that. The mission is pointless and scientifically worthless. Good for jobs in the space industry so that does count for something.

Yeah yeah yeah. And there were those guys in ancient Greece who were ranting about wasting good fabric that could be used for useful things like togas on sails on boats that could do just as well with a few oarsmen. They saw no practical value in being able to boat from island to island, since there was nothing on fabled Crete or the delta of the Nile that could not be fashioned from the stuff within a donkey's trot of Athens.

While I don't have a high opinion of the SLS stack or of Congressional pork... One of the problems NASA is faced with is justifying their existence, which in the public eye (i.e. our representatives in Congress) has to include some form of manned spaceflight. This while not having the funding wherewithal (as provided by the same Congressional representatives) to complete a flagship manned planetary or lunar exploration program.

You can't completely discount manned spaceflight as having absolutely no scientific value; because, there is scientific and technical value in performing a manned mission to an asteroid parked in orbit. There's a quote that goes something like: "A geologist with a rock hammer could learn more in an hour than the robotic probe learned in a year." It's a gross oversimplification but there's some validity to it. By putting people on the site, we can learn quite a bit about the makeup and structure of the sample asteroid that might not be possible with a single pre-designed robotic probe, regardless of how well designed. A human in-situ can make observations and connections based on experience that a robot might not be equipped to make. Said human could then make decisions based on that information, which might be different than decisions made by a remote operator.

In addition, in the process of designing and flying the vehicle we gain valuable technical information necessary to support various human. We get improved engine designs for vehicles, human or robotic. We get better life-support designs which can be applicable to terrestrial applications as well as space. We get better harsh environment suits. We test the ability of our systems to support "long-endurance" human spaceflight outside the cozy protected orbit ISS resides in.

Now, if your argument is simply that we shouldn't be putting humans into space at all, as it's too dangerous and/or expensive... I don't know that I have a counter argument that you'll find acceptable. Sure, we can do some things more cheaply using robots and automation. That's true with many human endeavors. McDonalds is working on automating food production in their restaurants, for example. Agriculture can be largely automated. Manufacturing can be automated. Art can be automated. We use human labor because humans are cheap(-er) than using machines or humans introduce artistic / cultural variation, or humans can make observations and connections based on experience that machines cannot (yet) make, or we just have a surplus of humans looking for something to do...

Sending people to space is expensive because of the energy cost (boost out of the gravity well) and life-support cost. There's no getting around the energy required to boost out of the gravity well; but, we can improve the vehicle and drive costs down. Life support costs we can reduce through infrastructure improvements. If we're ever to have any kind of presence in space, we have to start somewhere; and, that's going to require putting humans into space to obtain experience that cannot be obtained remotely via robotic telepresence. If we're going to reduce the cost, we have to build infrastructure, which is largely going to require some human supervision. We're going to go there eventually; the root technology is available now.

It takes more than a year to get the robot to the surface with it's instruments. These robotic probes are often a decade in planning, manufacture, testing, integration and launch. In fact, the robotic probe will likely be sent on a slower, less energetic path; so, it will take longer to get there. That's not the point. In the same amount of time on the surface, the human can accomplish considerably more.

All the exciting missions lately have been robotic such as the Curiosity (MSL) Mars Rover, Cassini, Voyager and next year the Pluto/Charon and Ceres missions. NASA management, all ex-astronauts and fighter jocks, hate this because they want to push their manned pork such as the SLS and Orion, but the public just does not care; there is no science or excitement there. This asteriod missions, which has no scientific value, is intended to get the public excited about manned missions.....snore...

Remote control cars on Mars are boring. They do nothing to advance anything except some mild bickering over how common bacteria is in our solar system.Asteroid capture does not do much by itself, but would serve as a meaningful proof of concept for the feasibility of extraplanetary construction. Many issues would still be unresolved, but it would show the availability of resources and provide a workspace to start testing ideas of how to extract, process, and manufacture with metals in a negligible gravity

The landing of the "boring" remote control car (the Curiosity rover) was a huge international event with more publicity than the ISS has ever had in its whole lifetime. It must have ticked off Bolden and the rest of the manned-spaceflight lobby at NASA to no end.
You seem to forget that Star Trek was not a documentary; robots can do anything man can do and much better at a tenth or hundredth of the cost.
The only science that the ISS, Orion, SLS, and this asteroid stunt will accomplish is be research on

robots can do anything man can do and much better at a tenth or hundredth of the cost.

Which robots can cover dozens of miles in a few days, while collecting the most interesting scientific specimens from that area?

The big disadvantage of robots is that they're damn slow. A human could cover the distance the Mars rovers have travelled in a day, but you could put a hundred or more rovers on Mars for the cost of putting one human there.

Not a lot. However, they've been in free fall around the Sun for as much as 4.5B years. The pile of rubble will pick up the odd grain of sand, chunk of ice or small piece of gravel every now and then as it orbits; and, it will stick together and grow. Or it will fly apart as was evidenced by Hubble sees asteroid breakup [space.com]

How much gravitational attraction does a six-meter pile of rubble even have?

Depends on the density, which varies by spectral class. Some asteroids are mostly iron, and have densities over 5g/cc. TFA doesn't mention the spectral class, but describes it as "rock" so it likely is non-iron. So let's assume a spherical shape with a density of 3g/cc or 3000 kg/m^3. Then the gravitational acceleration at the surface would be: 6.674e-11 x (3000 * 4/3 * pi * 3^3) / 3^2 = 8.4e-7 m/s^2 or about ten million times weaker than Earth's surface gravity. Unless I made a mistake somewhere.

The composition of asteroids is fairly well-known, both from the numerous meteorites we've recovered, and from the numerous spacecraft missions, including a sample return (Hayabusa). Unmanned probes can't do nearly the same scope of exploration as a manned mission, but asteroids are small. Does one even deserve a manned mission, much less several manned missions?

What is there to be gained from an asteroid capture and manned exploration? I'm all for manned exploration,

Pure pork that's all.
The money would be better spent on Mars, or Europa missions or even Enceladus or Titan.
The current NASA administration (and White House) have been a disaster for planetary science. They are not putting anything in the pipeline....

My idea was to use a nuclear powered craft that once it latches on to its first asteroid, it then extracts small pieces of it, and fires them out like projectiles to move it to the next asteroid. You could even launch asteroids back towards earth if you're feeling lucky:P I don't hear anyone talking about using Asteroid rocks as the kinetic matter for propulsion. I just thought it was a unique thought to share with the community.

Right, that is the standard approach. Use hydrogen with particle accelerators which people are calling ion engines now.

It is just that the asteroids produce an interesting situation where if you had a rock cannon, you could use the asteroids as propellant. It is probably a bad idea though because it is like wasting asteroid material which could be used for research. Another idea would to have a sort of "leaping" robot which wouldn't deplete the asteroid's mass, but would jump from asteroid to asteroid

That asteroid may just be a collection of small rocks held together with a VERY small gravitational glue, not some single big rock. One may need a bag to caputure it and move it anywhere. Tyvec or some metal mesh may do.